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1 /*
2  * Copyright (c) 2008, 2009, Google Inc. All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions are
6  * met:
7  *
8  *     * Redistributions of source code must retain the above copyright
9  * notice, this list of conditions and the following disclaimer.
10  *     * Redistributions in binary form must reproduce the above
11  * copyright notice, this list of conditions and the following disclaimer
12  * in the documentation and/or other materials provided with the
13  * distribution.
14  *     * Neither the name of Google Inc. nor the names of its
15  * contributors may be used to endorse or promote products derived from
16  * this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #ifndef XBMImageDecoder_h
32 #define XBMImageDecoder_h
33 
34 #include "ImageDecoder.h"
35 
36 namespace WebCore {
37 
38     // This class decodes the XBM image format.
39     class XBMImageDecoder : public ImageDecoder {
40     public:
41         XBMImageDecoder();
~XBMImageDecoder()42         virtual ~XBMImageDecoder() {}
43 
filenameExtension()44         virtual String filenameExtension() const { return "xbm"; }
45 
46         virtual void setData(SharedBuffer* data, bool allDataReceived);
47         // Whether or not the size information has been decoded yet.
48         virtual bool isSizeAvailable();
49         virtual RGBA32Buffer* frameBufferAtIndex(size_t index);
50 
51     private:
52         // Restricts image size to something "reasonable".
53         // This protects agains ridiculously large XBMs and prevents bad things
54         // like overflow of m_bitsDecoded.
55         static const int maxDimension = 65535;
56 
57         // In X10, an array of type "short" is used to declare the image bits,
58         // but in X11, the type is "char".
59         enum DataType {
60             Unknown,
61             X10,
62             X11,
63         };
64 
65         bool decodeHeader();
66         bool decodeDatum(uint16_t* result);
67         bool decodeData();
68         void decode(bool sizeOnly);
69 
70         // FIXME: Copying all the XBM data just so we can NULL-terminate, just
71         // so we can use sscanf() and friends, is lame.  The decoder should be
72         // rewritten to operate on m_data directly.
73         Vector<char> m_xbmString;  // Null-terminated copy of the XBM data.
74         size_t m_decodeOffset;    // The current offset in m_xbmString for decoding.
75         bool m_allDataReceived;
76         bool m_decodedHeader;
77         enum DataType m_dataType;
78         int m_bitsDecoded;
79     };
80 
81 } // namespace WebCore
82 
83 #endif
84